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（同濟(jì)大學(xué)土木工程學(xué)院， 上海 200092）

［摘要］采用自行研發(fā)的受扭試驗(yàn)裝置，研究采用組合封閉箍筋且兩次澆筑的混凝土疊合梁受扭性能。對(duì)比試驗(yàn)分2批，第一批試驗(yàn)包括12根梁試件，研究參數(shù)考慮箍筋形式和配筋率。第二批試驗(yàn)包括8根梁試件，參數(shù)選取澆筑方式和配筋率。研究表明，相比采用傳統(tǒng)箍筋的梁，采用組合封閉箍筋的梁受扭極限承載力降低幅度約3-7%。疊合界面的存在對(duì)梁受扭也有不利影響。第二次澆筑的強(qiáng)度較高的混凝土有助于提高梁受扭極限承載力，研究顯示提高幅度約6-7%?？梢越普J(rèn)為組合封閉箍筋疊合梁與傳統(tǒng)箍筋整澆梁具有相同的受扭性能，前者受扭極限承載力設(shè)計(jì)值仍采用我國(guó)規(guī)范推薦的方法計(jì)算。

［關(guān)鍵詞］組合封閉箍筋； 疊合梁； 極限扭矩； 試驗(yàn)研究

中圖分類號(hào)：TU375-1文獻(xiàn)標(biāo)識(shí)碼：A文章編號(hào)：1002-848X(2018)18-0064-04

Experimental study on torsion behaviors of RC beams with two-piece enclosed stirrups

Lin Feng, Zhang Zhi, Wang Qing

(College of Civil Engineering, Tongji University, Shanghai 200092, China)

Abstract:Torsion behaviors of reinforced concrete beams with two-piece enclosed stirrups  and cast in tow times were investigated using a self-developed torsion test device. The test program was divided into two groups. The first group included twelve beam  specimens considering different stirrup forms and reinforcement ratios. The second group included eight beam specimens considering different casting forms and reinforcement ratios. The results indicates that torsion ultimate bearing capacities of beams reinforced with two-piece enclosed stirrups decreased by about 3-7% compared to those reinforced with traditional stirrups. The torsion performance was also detrimentally affected by the presence of concrete to concrete interface. The second-cast concrete with higher strength helps to increase the torsional ultimate bearing capacity of the beam about 6-7%. It can be approximated that the beams with two-piece enclosed stirrups have the same torsion performance as the reinforcement beams with conventional stirrups. The design value of the  torsional ultimate bearing capacity of the beams with two\|piece enclosed stirrups can still be calculated by the method recommended by China′s specifications.

Keywords:two-piece stirrup; composite beam; ultimate torsion; experimental study

*同濟(jì)大學(xué)土木工程學(xué)院光華基金課題。

作者簡(jiǎn)介：林峰，博士，研究員，Email: lin_feng@#edu.cn。